Vapor-coating apparatus



Feb 7, 1967 P. MULLER 3,303,320

VAPOR- COATI NG APPARATUS Original Filed Sept. 10, 1963 2 Sheets-Sheet 1I 4- f 4 l 8/ 1W im m i j 4 f J3 INVENTOR Pay/Muller ATTORNEY Feb. 7,1967 P. MULLER VAPOR-COATING APPARATUS Original Filed Sept. 10. 1963 2Sheets-Sheet 2 VIM- INVENTOR 7 47 u Mu/Aer United States Patent3,303,320 VAPOR-COATING APPARATUS Paul Muller, Hanan am Main, Germany,assignor to W. C. Heraeus Gesellschaft mit beschrankter Haftung, Hananam Main, Germany, a corporation of Germany Continuation of applicationSer. No. 307,954, Sept. 10, 1963. This application June 21, 1966, Ser.No. 562,066 Claims priority, application Germany, Sept. 25, 1962, H46,998 8 Claims. (Cl. 219-121) The present invention relates to avapor-coating apparatus in which a material is heated and vaporized in avacuum chamber by an electron beam and the vapor is deposited upon anobject, and this application is a continuation of my co-pendingapplication Serial No. 307,954 which was filed September 10, 1963.

Apparatus of this general type employing electron beams for heating thematerial to be vaporized are known for some time. They have several veryimportant advantages over vapor-coating apparatus which employ otherheating means, for example, by electric resistance. When heating thematerial to be vaporized by resistance heating in long vaporizercrucibles, strong heating currents are passed through the liquidmaterial and the outer circuit exerts electrodynamic forces upon thematerial which very easily cause the liquid material to creep upwardlyalong the walls and then to flow out of the crucible. Since theseelectrodynamic forces do not occur when the material is heated in thelong vaporizer crucibles by means of electron beams, such spilling ofmaterial is avoided. Furthermore, the localized, spotlight heating ofthe material by means of an electron beam results in a very quickvaporization which tends to prevent a dissociation or disproportionationof certain compounds which occurs when the heating occurs slowly byresistance heating and which may be very undesirable in the coatingproduced.

The electron beams which are used for vaporizing apparatus are generallyfocused so as to be of a substantially cylindrical cross section. Suchan electron beam heats practically only the relatively small spot whereit hits upon the material to be vaporized so that a vaporization alsooccurs only at this small spot. In order to heat a larger surface areaof the material, so-called transverse electron guns have already beendeveloped which instead of substantially cylindrical electron beamsproduce beams of a substantially rectangular ribbonlike cross sectionfor heating metals to the melting point. Such ribbonlike beams aresuperior to the cylindrical beams insofar as they permit a vaporizercrucible to be heated longitudinally for a certain distance. Thesedistances are, however, still insufiicient for properly coating widerbands of material by vapor-deposition.

It is an object of the present invention to provide a vapor-coatingapparatus of a very simple and inexpensive construction which overcomesthe last-mentioned disadvantage and is designed for coating wide bandsof materials in a vacuum by heating the vaporizing material by means ofelectron beams which are produced in the form of ribbonlike beams bytransverse electron guns. For attaining this object, the inventionessentially consists in mounting a plurality of transverse electron gunsin a row in a magnetic field which is formed by a pair of long plateswhich form or are provided with pole pieces. These electron guns arespaced at relatively short distances from each other for shootingelectron beams either into a corresponding number of elongated vaporizercrucibles or into one long vaporizer tray.

The above-mentioned as well as further features and advantages of thepresent invention will become more clearly apparent from the followingdetailed description thereof which is to be read with reference to theaccompanying diagrammatic drawings in which only the essential featuresof the invention are illustrated, while the conventional parts of theapparatus are omitted, and in which:

FIGURE 1 shows a plan view of an apparatus according to the invention inwhich the beam tension or beam velocity in electron-volts and thestrength of the magnetic flux are coordinated in such a manner that eachelectron beam will impinge upon the material in the vaporizer crucibleadjacent to the respective electron gun;

FIGURE 2 shows a cross section which is taken along the line aa ofFIGURE 1;

FIGURE 3 shows a modification of the invention in which each electronbeam impinges upon the material in the vaporizer crucible following thenext crucible;

FIGURE 4 shows a view, partly in cross section, of an apparatus withexchangeable pole pieces;

FIGURE 5 shows a preferred embodiment of the invention with inclinedmagnetic pole plates;

FIGURE 6 shows a partial elevation of an apparatus with arcuate controlelements;

FIGURE 7 shows a cross section which is taken along the line b-b ofFIGURE 6; while FIGURE 8 shows the application of the invention to asingle long vaporizer tray.

Referring to the drawings and first particularly to FIG- URES l and 2,the apparatus according to the invention essentially comprises arotatable roller 1 which is mounted within the outer housing of avaporizing chamber, not shown, which may be evacuated and opened in aconventional manner. This roller 1 carries the band or web of material 2which is to be coated by vapor-deposition and which is conveyed by amechanism which may also be of a conventional type and is therefore notillustrated. Underneath the roller 1 a series of vaporizer crucibles 4are located, the longitudinal axes of which extend transverse to thelongitudinal axis of roller 1. In order to attain a uniformvapor-coating on web 2 across its entire width the crucibles 4 arepreferably spaced from the roller 1 at a distance which is at leastequal to the distance between the adjacent crucibles.

Between the adjacent crucibles 4 transverse electron guns 5 are mountedfrom which electron beams 6 emerge first in the general direction towardroller 1. These ribbon-like beams 6 are then deflected by the magneticfield H in a manner so as to impinge upon the material in the crucible 4adjacent to the respective gun 5 and thus to heat and vaporize thismaterial.

The magnetic field H is produced by a pair of plates 7 which consist,for example, of soft iron and are magnetized by the coils 8 and themagnet yokes 9. These magnet yokes 9 are connected to the plates 7 byyoke arms 10 which may be provided at different points and of differentcross-sectional sizes so as to insure that the magnetic field will beuniform.

The magnetic field and the beam tension or the beam velocity inelectron-volts may also be coordinated in the manner as illustrated inFIGURE 3 so that the electron beam 12 of each gun 5 will impinge uponthe material in the vaporizer crucible 4 following the next crucible orin a crucible which is still more remote from the respective gun 5.

As indicated in FIGURE 4, it is advisable to provide the plates 7 withremovable pole pieces 13 so as to permit them to be easily exchanged inthe event that vaporlayers of too great a thickness have been depositedthereon.

For homogenizing the magnetic field H, it is also advisable asillustrated in FIGURE 5, to mount the plates 7 so as to extend at aslight inclination to the axis 14 of the apparatus and in a manner sothat at their points of connection to the yoke arms 10 they will bespaced at the greatest distance from the axis 14. In order to make themagnetic field very uniform or to guide each ribbonlike electron beam 6very accurately, it is also possible, as shown in FIGURES 6 and 7, tomount arcuate control elements 15 on the plates 7.

Instead of providing a series of vaporizer crucibles 4 as shown inFIGURES 1 to 3, it is also possible to provide a single long vaporizertray 16, as shown in FIG- URE 8. The transverse electron guns are inthis case mounted above the crucible 16 and they are preferablyprotected from a vapor deposition by shields 17 which are preferablyheated to such a high temperature that the vapor will not adherethereto. Of course, it is also possible to protect other parts of theapparatus from vapor deposition, especially the supporting insulators ofthe electron guns 5 and their current leads.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments, but iscapable of numerous modifications within the scope of the appendedclaims.

Having thus fully disclosed my invention, what I claim 1. An apparatusfor coating wide bands of materials by vapor deposition in a vacuumcomprising a plurality of elongated transversely disposed electron gunsand a like number of transversely disposed elongated crucibles, each ofwhich is adapted to contain a certain material to be vaporized, saidelectron guns and said crucibles being alternately arranged in spacedrelation to each other in a longitudinally extending row, means forproducing a magnetic field comprising a pair of magnetic yoke means anda pair of elongated plates forming pole pieces, said plates beingdisposed in spaced opposed relation to each other one on each side ofsaid longitudinally extending row and extending from end to end of saidrow, connecting means by which said plates are connected to said yokes,said plates and said connecting means being effective to produce asubstantially uniform magnetic field between said plates throughout thelength thereof, each of said electron guns being adapted to shoot aribbon-like electron beam into one of said crucibles to heat andvaporize the material therein, the velocity of said electron beams, andthe strength of said magnetic field being co ordinated in such a mannerthat the electron beam of each gun is deflected so as to be directedinto the next succeeding adjacent crucible in said longitudinallyextending row of electron guns and crucibles.

2. An apparatus for coating wide bands of material by vapor depositionas defined by claim 1 in which said connecting means comprises aplurality of spaced parallel yoke arms, one of said arms being connectedto and between the mid-section of each of said plates and one of saidyokes, and other of said arms being connected to and between each ofsaid plates and one of said yokes between the mid-section of each plateand each end thereof, the cross-sectional area of the said other of saidarms being less than the cross-sectional area of the said one of saidarms.

3. An apparatus for coating wide bands of material by vapor depositionas defined by claim 1 in which said connecting means comprises a pair ofyoke arms one of which is connected between the mid-section of each ofsaid plates and one of said yokes; and in which said plates convergebetween the mid-sections thereof and each of the ends thereof.

4. An apparatus for coating wide bands of material by vapor depositionin a vacuum comprising a plurality of transversely disposed electronguns which are arranged in spaced relation to each other in alongitudinally extending row, means which is disposed in spaced relationto said electron guns and is adapted to contain a certain material to bevaporized, means for producing a magnetic field comprising a pair ofmagnetic yoke means and a pair of elongated plates forming pole pieces,said plates being disposed in spaced opposed relation to each other oneon each side of said longitudinally extending row and extending from endto end of said row, connecting means by which said plates are connectedto said yokes, said plates and said connecting means being effective toproduce a uniform magnetic field between said plates throughout thelength thereof, each of said electron guns being adapted to shoot aribbon-like electron beam into said container means to heat and vaporizethe material therein, the velocity of said electron beams and thestrength of said magnetic field being coordinated in such a manner thatthe electron beam of each gun is deflected so as to be directed intosaid first mentioned means.

5. An apparatus for coating wide bands of material by vapor depositionin a vacuum comprising a plurality of transversely disposed electronguns which are arranged in spaced relation to each other in alongitudinally extending row, an elongated longitudinally extending traywhich is disposed below said longitudinally extending row of electronguns in vertically spaced relation thereto and extends from end to endof said row and is adapted to contain a certain material to bevaporized, means for producing a magnetic field comprising a pair ofmagnetic yoke means and a pair of elongated plates forming pole pieces,said plates being disposed in spaced relation to each other one on eachside of said longitudinally extending row and extending from end to endof said row, connecting means by which said plates are connected to saidyokes, said plates and said connecting means being effective to producea substantially uniform magnetic field between said plates throughoutthe length thereof, each of said electron guns being adapted to shoot aribbonlike electron beam into said container means to heat and vaporizethe material therein, the velocity of said electron beams and thestrength of said magnetic field being coordinated in such a manner thatthe electron beam of each gun is deflected so as to be directed intosaid tray.

6. An apparatus for coating wide bands of material by vapor depositionas defined by claim 5 in which said connecting means comprises aplurality of spaced parallel yoke arms, one of said arms being connectedto and between the mid-section of each of said plates and one of saidyokes, and other of said arms being connected to and between each ofsaid plates and one of said yokes between the mid-section of each plateand each end thereof, the cross-sectional area of the said other of saidarms being less than the cross-sectional area of the said one of saidarms.

7. An apparatus for coating wide bands of material by vapor depositionas defined by claim 5 in which said connecting means comprises a pair ofyoke arms one of which is connected between the mid-section of each ofsaid plates and one of said yokes; and in which said plates convergebetween the mid-sections thereof and each of the ends thereof.

8. An apparatus for coating wide bands of material by vapor depositionas defined by claim 1 in which the opposed faces of said pair of platesare each provided with a plurality of pairs of spaced concentric controlelements by which the electron beams emitted by each of said electronguns is guided into an adjacent crucible.

References Cited by the Examiner UNITED STATES PATENTS 2,932,588 4/1960Frank.

3,036,549 5/1962 Iwata et al. ll849.l 3,043,728 7/1962 Stautfer 1l8-49 X3,046,936 7/1962 Simons.

3,170,019 2/1965 Hanks 13-31 3,172,007 3/1965 Hanks et al. 13-31 X3,183,563 5/1965 Smith 118-49.l

JOSEPH V. TRUHE, Primary Examiner.

1. AN APPARATUS FOR COATING WIDE BANDS OF MATERIALS BY VAPOR DEPOSITIONIN A VACUUM COMPRISING A PLURALITY OF ELONGATED TRANSVERSELY DISPOSEDELECTRON GUNS AND A LIKE NUMBER OF TRANSVERSELY DISPOSED ELONGATEDCRUCIBLES, EACH OF WHICH IS ADAPTED TO CONTAIN A CERTAIN MATERIAL TO BEVAPORIZED, SAID ELECTRON GUNS AND SAID CRUCIBLES BEING ALTERNATELYARRANGED IN SPACED RELATION TO EACH OTHER IN A LONGITUDINALLY EXTENDINGROW, MEANS FOR PRODUCING A MAGNETIC FIELD COMPRISING A PAIR OF MAGNETICYOKE MEANS AND A PAIR OF ELONGATED PLATES FORMING POLE PIECES, SAIDPLATES BEING DISPOSED IN SPACED OPPOSED RELATION TO EACH OTHER ONE ONEACH SIDE OF SAID LONGITUDINALLY EXTENDING ROW AND EXTENDING FROM END TOEND OF SAID ROW, CONNECTING MEANS BY WHICH SAID PLATES ARE CONNECTED TOSAID YOKES, SAID PLATES AND SAID CONNECTING MEANS BEING EFFECTIVE TOPRODUCE A SUBSTANTIALLY UNIFORM MAGNETIC FIELD BETWEEN SAID PLATESTHROUGHOUT THE LENGTH THEREOF, EACH OF SAID ELECTRON GUNS BEING ADAPTEDTO SHOOT A RIBBON-LIKE ELECTRON BEAM INTO ONE OF SAID CRUCIBLES TO HEATAND VAPORIZE THE MATERIAL THEREIN, THE VELOCITY OF SAID ELECTRON BEAMS,AND THE STRENGTH OF SAID MAGNETIC FIELD BEING COORDINATED IN SUCH AMANNER THAT THE ELECTRON BEAM OF EACH GUN IS DEFLECTED SO AS TO BEDIRECTED INTO THE NEXT SUCCEEDING ADJACENT CRUCIBLE IN SAIDLONGITUDINALLY EXTENDING ROW OF ELECTRON GUNS AND CRUCIBLES.